Date: Fri, 13 Aug 2004 08:20:23 GMT From: Pawel Malachowski <pawmal-posting@freebsd.lublin.pl> To: ipfw@FreeBSD.org Subject: Re: kern/46557: ipfw pipe show fails with lots of queues Message-ID: <200408130820.i7D8KN21062944@freefall.freebsd.org>
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The following reply was made to PR kern/46557; it has been noted by GNATS.
From: Pawel Malachowski <pawmal-posting@freebsd.lublin.pl>
To: Pawel Malachowski <pawmal-posting@freebsd.lublin.pl>
Cc: freebsd-gnats-submit@FreeBSD.org
Subject: Re: kern/46557: ipfw pipe show fails with lots of queues
Date: Fri, 13 Aug 2004 10:13:35 +0200
On Thu, Aug 12, 2004 at 07:30:25PM +0000, Pawel Malachowski wrote:
> Here are more details what is going on. I hope someone will look at this and
> explain why malloc() can fail here and what can be done to prevent this.
Well, I will explain myself. First, a patch:
*** ip_dummynet.c.orig Fri Aug 13 09:51:54 2004
--- ip_dummynet.c Fri Aug 13 09:52:23 2004
***************
*** 1833,1839 ****
for (set = all_flow_sets ; set ; set = set->next )
size += sizeof ( *set ) +
set->rq_elements * sizeof(struct dn_flow_queue);
! buf = malloc(size, M_TEMP, M_NOWAIT);
if (buf == 0) {
splx(s);
return ENOBUFS ;
--- 1833,1839 ----
for (set = all_flow_sets ; set ; set = set->next )
size += sizeof ( *set ) +
set->rq_elements * sizeof(struct dn_flow_queue);
! buf = malloc(size, M_TEMP, M_WAITOK);
if (buf == 0) {
splx(s);
return ENOBUFS ;
Since buf can be very big (on my system, up to 3MB), malloc typically
consumes only 128k-512k buckets (as checked in vmstat -m). On heavy
loaded system with huge number of pipes, there is a risk that first-fit
strategy won't find memory because of fragmentation.
We will change M_NOWAIT to M_WAITOK flag so malloc() will always succeed;
dummynet_get() is called only when superuser runs `ipfw pipe show', so
WAITOK is not a problem for us.
--
Paweł Małachowski
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